mulch pile wall

In the process of design a containment system for mulch and stone deliveries. I would like to keep the two seperate but right next to each other. Any ideas on what I should use to build a "U" shapped wall to hold the mulch?
If I get deliveries over 50yds....how big will the "U" shaped wall need to be?
I was thinking of building something out of 8'x8' posts sticking out of the ground with 12" wide slats all around?
WIll the 8'x8' posts(in concrete) hold the deliveries of mulch and stone?
I looked into the concrete barriers but I am not sure I like the looks and they are kinda of cost prohibitive!

pretty much anything will hold mulch, we used a chain link fence attatched to 4 inch posts, every 4 feet with 1and 1/2 inch horizontal runners every two feet. For gravel and stone we attatched used guard rail to the same spacing of pipes, and it never fell over. The wood should hold the mulch but watch out when you need to scoop it out with the loader. Using a backhoe or good sized wheel loader improperly could compress the mulch and damage the fence. If you wanted to use wood for holding stones, why not try RR ties , some stuck in the ground and the others stacked up? That was a common way of holding gravel in nurseries here.

go to a concrete manufactureing plant. they usuallyhave large blocks, 6'x3'x3' they call them over pours. basicaly when a truck comes back to the plant and a bit of extra crete they dump it in a form. around here they sell them for 25 bucks each...it takes some doing to get em home,, they weigh about 4000 lbs. They also usuallyhave a groove cut in the bottom and raised channel on the top so you can interlock them.. We have stacked them 3 high with out any back suport and have no problems...

youcould always buy some Jersey Barriers.....

when you figure out your size just pretend your drop area is a cube and length x Width X height to get a rough value on cubic space, sice mulch in delivered in cubic yards you'd be close enough...

PM me so I don't forget I have some pictures at work...and I'll post em...

Marc....thanks for the response. For some reason I can not pm yet. Anyways the muclh pile and stone piles are going to be out front of my shop so I want to make the barriers look nice and professional.

Pics 1 and 2 are from the bins I built at TruGreen each bin holds about 20 yards, I had two mulch bins wich held 200yds each. but they are not pictured

Pics 3 and 4 are of a Sand/salt bin a client wanted us to build on their site for their sand and salt. these are free standing I showed a closeup of the rebar block movement preventions system we came up with.... Hope this helps give folks an idea.

Around here, most of the guys use the blocks from the concrete companies-I've notice that some of them look pretty rough, but one or two of the company makes really nice looking ones. This is what I'm planning to use, i just have to arrange a loader for a day to move them around. As far as the mulch is concererned, most of the companies just have those in their own piles, with no barriers. Right now I've got mine in an indepentant pile, soon though, i'd like to have a back wall, mainly for pushing against when loading, and the pile is small.